Electric motors may be used to drive gears to achieve actuation, or mechanical displacement, as in automotive window lift mechanisms. Some motors include an armature shaft with a worm drive section. This shaft rotates and drives worm gears. In any application it is necessary that the gears be driven reliably and with minimal vibration and noise. During use armature shafts may break undesirably under load when the worm drive section engages the gears. Since reliability is a key requirement for a motor, there is a desire for reliability testing of various designs to determine if they will satisfy cycle life requirements prior to breakage of the armature shaft.
Typically this testing is done by running assembled motors under various conditions. However, this method is problematic. Since the motor requires dynamic time as well as dwell time during testing, the testing is time consuming and cannot be accelerated. Furthermore, the test results can be difficult to interpret due to variations between motors. In addition, using complete motors requires assembly of the motor which is time consuming.